Question

How to sum 2D array (matrix) rows in PHP

Answer 1

function sum_matrix_rows($arr, &$rows_sum)
{
    $rows = count($arr);
    $cols = count($arr[0]);
     
     for ($i = 0; $i < $rows; $i++) {
        for ($j = 0; $j < $cols; $j++)
            $rows_sum[$i] += $arr[$i][$j];
   }
}
 
$arr = array(
    array(11, 32, 13),
    array(20, 80, 990),
);
$rows_sum = array(0,0);

sum_matrix_rows($arr, $rows_sum);

 for ($i = 0; $i < 2; $i++) 
      echo $rows_sum[$i] . "<br />\n";
      
 
/*
run:
 
56
1090  
    
*/

 

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